U.S. patent application number 15/335517 was filed with the patent office on 2017-02-16 for pressure sensitive stylus for a digitizer.
This patent application is currently assigned to Microsoft Technology Licensing, LLC. The applicant listed for this patent is Microsoft Technology Licensing, LLC. Invention is credited to Yuval STERN.
Application Number | 20170045961 15/335517 |
Document ID | / |
Family ID | 52625133 |
Filed Date | 2017-02-16 |
United States Patent
Application |
20170045961 |
Kind Code |
A1 |
STERN; Yuval |
February 16, 2017 |
PRESSURE SENSITIVE STYLUS FOR A DIGITIZER
Abstract
A pressure sensitive stylus for operation with a digitizer
sensor includes a housing, a writing tip that is movable in
response to contact pressure applied on the writing tip, an
extremity that is movable together with the writing tip, a switch
and an elastomer element positioned around the extremity and in
physical contact with at least one of the housing or an element
that is fixed to the housing. The switch includes a first element
that is fixedly positioned around the extremity and a second
element that is fixed to the housing, wherein physical contact
between the first element and the second element closes the switch.
The writing tip is operable to move in response to the elastomer
element compressing against the housing or an element that is fixed
to the housing and the switch is operative to toggle at a
pre-defined compressed state of the elastomer element.
Inventors: |
STERN; Yuval; (Even-Yehuda,
IL) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Microsoft Technology Licensing, LLC |
Redmond |
WA |
US |
|
|
Assignee: |
Microsoft Technology Licensing,
LLC
Redmond
WA
|
Family ID: |
52625133 |
Appl. No.: |
15/335517 |
Filed: |
October 27, 2016 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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14451448 |
Aug 5, 2014 |
9513721 |
|
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15335517 |
|
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61876888 |
Sep 12, 2013 |
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14451448 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
G06F 2203/04105
20130101; G06F 3/03545 20130101; G06F 3/0383 20130101; G06F 3/041
20130101; G06F 3/0442 20190501; G06F 2203/04101 20130101; G06F
3/044 20130101 |
International
Class: |
G06F 3/0354 20060101
G06F003/0354; G06F 3/044 20060101 G06F003/044; G06F 3/038 20060101
G06F003/038 |
Claims
1. A pressure sensitive stylus for operation with a digitizer
sensor comprising: a housing; a writing tip that is movable and
recedes toward the housing of the stylus in response to contact
pressure applied on the writing tip; an extremity that is movable
together with the writing tip; a switch comprising: a first element
that is fixed to the extremity; a second element that is fixed to
the housing, wherein the first element and second element are
conductive and physical contact between the first element and the
second element initiates electrical communication and toggles the
switch; a third element that is fixed to the housing; a controller
configured to detect the electrical communication; and an resilient
element positioned around the extremity, the resilient element
including a base surface and at least one protruding surface
extending from the base surface, wherein the at least one
protruding surface maintains physical contact with the third
element during toggling of the switch, and wherein the base surface
is configured to move with respect to the third element during the
toggling, wherein the resilient element is configured to compress
against the third element based on the contact pressure applied on
the writing tip; and wherein the switch is configured to toggle at
a pre-defined compressed state of the resilient element.
2. The pressure sensitive stylus of claim 1, wherein toggling of
the switch defines a transition between a hover operational state
and a touch operational state of the stylus.
3. The pressure sensitive stylus of claim 1, wherein toggling of
the switch defines a transition between a sleep mode and an active
mode of the stylus.
4. The pressure sensitive stylus of claim 1, wherein the switch is
operable to alter at least one of a repetition rate, a duty cycle
and a power state of the stylus.
5. The pressure sensitive stylus of claim 1, comprising: a
transmitting unit for transmitting the operational state of the
stylus to a digitizer sensor that is operated together with the
stylus.
6. The pressure sensitive stylus of claim 1, wherein the second
element includes two terminals and wherein contact between the
first element and the second element shorts the two terminals.
7. The pressure sensitive stylus of claim 1, wherein the first
element or the second element is formed from a conductive material
that is pliable.
8. The pressure sensitive stylus of claim 7, wherein the first
element or the second element is formed from conductive particles
embedded in at least one of silicon, rubber, thermoplastic
polyurethane and polyoxymethylene.
9. The pressure sensitive stylus of claim 1, wherein the resilient
element is integral to the first element or the second element.
10. The pressure sensitive stylus of claim 1, wherein the switch is
operative to toggle in response to the at least one protruding
element resiliently collapsing due to the resilient element
compressing against the third element.
11. The pressure sensitive stylus of claim 1, wherein the switch is
a normally closed switch, and wherein the first and second element
of the switch is separated responsive to the writing tip receding
toward the housing of the stylus.
12. The pressure sensitive stylus of claim 1, wherein the switch is
a normally open switch, and wherein the first and second element of
the switch is brought into contact responsive to the writing tip
receding toward the housing of the stylus.
13. The pressure sensitive stylus of claim 12, wherein the first
element includes a plurality of through going holes and the at
least one protruding element includes a plurality of protruding
elements and wherein the plurality of through going holes are
configured to match the plurality of protruding elements, and
wherein the first element is fitted on the resilient element so
that the plurality of protruding elements protrude through the
plurality of through going holes.
14. The pressure sensitive stylus of claim 13, wherein the second
element and the third element are a common element and wherein the
plurality of protruding elements are positioned to physically
contact the second element of the switch and are sized to separate
the first element of the switch from the second element of the
switch over a pre-defined displacement of the writing tip
associated with a hover operational state of the stylus.
15. The pressure sensitive stylus of claim 1, wherein the first
element comprises a first conductive layer and the second element
comprises a second conductive layer such that the first and second
conductive layers face each other, wherein a first conductive layer
is laminated with a non-conductive layer having a defined
dielectric coefficient, and wherein during an open state of the
switch a dielectric coefficient of an air gap that forms between
the non-conductive layer and the second conductive layer dominates
a combined dielectric coefficient of the air gap and non-conductive
layer.
16. The pressure sensitive stylus of claim 15, wherein the
controller is configured to detect changes in capacitance in the
switch responsive to movement of the writing tip.
17. The pressure sensitive stylus of claim 1, comprising: a
displacement monitor operative to monitor displacements of the
writing tip over a range of displacements; a controller operative
to sample output from the displacement monitor, wherein the range
of displacements is a range corresponding to a touch operational
mode of the stylus; and a transmitting unit operative to transmit
information associated with the output sampled to a digitizer
sensor operated together with the stylus, wherein at least one of
sampling output from the displacement monitor and transmitting
information associated with the output sampled is responsive toggle
state of the switch.
18. The pressure sensitive stylus of claim 1, wherein the base
surface of the resilient element is shaped as a flat ring.
19. The pressure sensitive stylus of claim 1, comprising: a sleeve
element movable between two partitions formed as part of the
housing, wherein the extremity is fitted through the sleeve element
and fixedly connect to the sleeve element so that tip movement is
confined by movement of the sleeve element.
20. A pressure sensitive stylus for operation with a digitizer
sensor comprising: a housing; a writing tip that is movable and
recedes toward the housing of the stylus in response to contact
pressure applied on the writing tip; an extremity that is movable
together with the writing tip; a switch comprising: a first
conductive layer fixedly positioned on an element positioned around
the extremity; and a second conductive layer facing the first
conductive layer, wherein the second conductive layer is fixed to
the housing; wherein one of the first conductive layer and the
second conductive layer is laminated with a non-conductive
material; and an resilient element including a base surface and one
or more protruding surfaces extending from the base surface;
wherein one of the first conductive layer and the second conductive
layer is integrated with the base surface and wherein the one or
more protruding surfaces extend from the base surface and toward
the other one of the first conductive layer and the second
conductive layer and is in physical contact with the other one of
the first conductive layer and the second conductive layer while
the switch is open and closed; and a controller configured to
detect electrical communication between the first conductive layer
and the second conductive layer; and wherein physical contact
between the first conductive layer and the second layer responsive
to compression of the resilient element closes the switch, wherein
the physical contact is detected by the controller as a change in
capacitance due to an absence of an air gap between the first and
second layer.
Description
RELATED APPLICATIONS
[0001] This application is a continuation of U.S. patent
application Ser. No. 14/451,448 filed on Aug. 5, 2014, which claims
the benefit of U.S. Provisional Patent Application No. 61/876,888
filed on Sep. 12, 2013. The contents of the above applications are
all incorporated by reference as if fully set forth herein in their
entirety.
FIELD OF THE INVENTION
[0002] The present invention, in some embodiments thereof, relates
to signal transmitting styluses used for interaction with digitizer
sensors, and more particularly, but not exclusively to styluses
that transmit signals responsive to pressure exerted on their
tip.
BACKGROUND OF THE INVENTION
[0003] Electromagnetic styluses are known in the art for use and
control of a digitizer. Position detection of the stylus provides
input to a computing device associated with the digitizer and is
interpreted as user commands. Position detection is performed while
the stylus tip is either touching and/or hovering over a detection
surface of the digitizer.
[0004] Often, the digitizer is integrated with a display screen and
a position of the stylus over the screen is correlated with virtual
information portrayed on the screen.
[0005] U.S. Patent Application Publication No. 20100051356 entitled
"Pressure Sensitive Stylus for a Digitizer" assigned to N-Trig
Ltd., the contents of which is incorporated herein by reference,
describes a pressure sensitive stylus with a movable tip that
recedes within a housing of the stylus in response to user applied
contact pressure and an optical sensor enclosed within the housing
for optically sensing the displacement of the tip and for providing
output in response to the sensing. It is disclosed that the
relationship between tip displacement and contact pressure and/or
the relationship between tip displacement and output of the optical
sensor can be non-linear.
[0006] Non-linearity can be achieved by non-linear properties of a
resilient element positioned to resist displacement of the tip, or
by shape of an aperture through which the optical signal of the
optical sensor is received.
[0007] U.S. Pat. No. 7,202,862 entitled "Pressure sensor for a
digitizer pen," the contents of which is incorporated herein by
reference, describes a digitizer pen that has a pressure sensor for
sensing pressure transferred from a writing tip. It is described
that an elastomer disk is mounted between a writing tip holder of
the pen and the pressure sensor. When the writing tip is pressed
against a sensing surface, such as a digitizer tablet, the end of
the stylus opposite the writing tip moves the tip holder against
the elastomer disk and transfers pressure from the tip holder to
the pressure sensor. At first the tip holder penetrates the
elastomer disk a certain amount and then in response to additional
pressure on the tip, the tip holder and elastomer disk moves toward
and actuates the pressure sensor. The force applied to the pressure
sensor by the elastomer disk is an input to the pressure
sensor.
[0008] U.S. Pat. No. 5,571,997 entitled "Pressure sensitive
pointing device for transmitting signals to a tablet," the contents
of which is incorporated herein by reference, describes a pressure
sensitive pen system. The force applied by a user results in
limited motion of the pen tip, the initial motion of which is
utilized to actuate a pen down switch; this switch actuation may be
used to provide a signal to be radiated by the pen to the tablet to
inform the latter that the pen is in contact with the tablet
surface.
[0009] Additional force applied by the user is subsequently
utilized as a means for varying the radiated frequency to provide a
basis for the tablet system to determine the force being used by
the user as the pen travels over the surface of the tablet.
[0010] U.S. Pat. No. 7,292,229 entitled "Transparent Digitizer"
which is assigned to N-trig Ltd., the contents of which is
incorporated herein by reference, describes a passive
electro-magnetic stylus which is triggered to oscillate at a
resonant frequency by an excitation coil surrounding a digitizer.
The oscillating signal is sensed by the digitizer. The stylus
operates in a number of different states including hovering, tip
touching, right click mouse emulation, and erasing. The various
states are identified by dynamically controlling the resonant
frequency of the stylus so that the stylus resonates at a different
frequency in each state. A position of the stylus, e.g. the stylus'
tip with respect to the digitizer sensor is determined based on
signals sensed from sensor.
SUMMARY OF THE INVENTION
[0011] According to an aspect of some embodiments of the present
invention, there is provided a stylus including a tip pressure
detecting system for monitoring contact pressure on a writing tip.
Typically, the tip pressure detecting system provides input for
switching between a hover operational mode (pen up) and a touch
operational mode (pen down) at a defined contact pressure on the
tip. Optionally, the system additionally provides for monitoring
different pressure levels within a touch operational mode (pen
down).
[0012] An aspect of some embodiments of the present invention
provides for a pressure sensitive stylus for operation with a
digitizer sensor comprising: a housing; a writing tip that is
movable and recedes toward the housing of the stylus in response to
contact pressure applied on the writing tip; an extremity that is
movable together with the writing tip; a switch comprising: a first
element that is fixedly positioned around the extremity; and a
second element that is fixed to the housing, wherein physical
contact between the first element and the second element closes the
switch; an elastomer element positioned around the extremity and in
physical contact with at least one of the housing or an element
that is fixed to the housing, wherein the writing tip is operable
to move in response to the elastomer element compressing against at
least one of the housing or an element that is fixed to the
housing; and wherein the switch is operative to toggle at a
pre-defined compressed state of the elastomer element.
[0013] Optionally, the pre-defined compressed state defines a
transition between a hover operational state and a touch
operational state of the stylus.
[0014] Optionally, the pre-defined compressed state defines a
transition between a sleep mode and an active mode of the
stylus.
[0015] Optionally, the switch is operable to alter at least one of
a repetition rate, a duty cycle and a power state of the
stylus.
[0016] Optionally, the pressure sensitive stylus includes a
controller operative to monitor toggling of the switch; and a
transmitting unit for transmitting the operational state of the
stylus to a digitizer sensor that is operated together with the
stylus.
[0017] Optionally, the first element is formed from a conductive
material, wherein the second element includes two terminals and
wherein contact between the first element and the second element
shorts the two terminals.
[0018] Optionally, the first element or the second element is
formed from a conductive material that is pliable.
[0019] Optionally, the first element or the second element is
formed from conductive particles embedded in at least one of
silicon, rubber, thermoplastic polyurethane and
polyoxymethylene.
[0020] Optionally, the elastomer element is integral to one of the
first element or the second element.
[0021] Optionally, the elastomer element includes a base surface
and at least one protruding element extending from the base surface
and wherein the switch is operative to toggle in response to the at
least one protruding element resiliently collapsing due to the
elastomer element compressing against the at least one of the
housing or the element that is fixed to the housing.
[0022] Optionally, the switch is a normally closed switch, and
wherein the first and second element of the switch is separated
responsive to the writing tip receding toward the housing of the
stylus.
[0023] Optionally, the switch is a normally open switch, and
wherein the first and second element of the switch is brought into
contact responsive to the writing tip receding toward the housing
of the stylus.
[0024] Optionally, the elastomer element includes a base surface
and a plurality of protruding elements extending from the base
surface, wherein the first element includes a plurality of through
going holes matching the plurality of protruding elements, and
wherein the first element is fitted on the elastomer element so
that the plurality of protruding elements protrude through the
plurality of through going holes.
[0025] Optionally, the plurality of protruding elements are
positioned to physically contact the second element of the switch
and are sized to separate the first element of the switch from the
second element of the switch over a pre-defined displacement of the
writing tip associated with a hover operational state of the
stylus.
[0026] Optionally, the first element comprises a first conductive
layer and the second element comprises a second conductive layer
such that the first and second conductive layers face each other,
wherein a first conductive layer is laminated with a non-conductive
layer having a defined dielectric coefficient, and wherein during
an open state of the switch a dielectric coefficient of an air gap
that forms between the non-conductive layer and the second
conductive layer dominates a combined dielectric coefficient of the
air gap and non-conductive layer.
[0027] Optionally, the pressure sensitive stylus includes a
controller operative to detect changes in capacitance in the switch
responsive to movement of the writing tip.
[0028] Optionally, the pressure sensitive stylus includes a
displacement monitor operative to monitoring displacements of the
writing tip over a range of displacements; a controller operative
to sample output from the displacement monitor; and a transmitting
unit operative to transmit information associated with the output
sampled to a digitizer sensor operated together with the
stylus.
[0029] Optionally, the range of displacements is a range
corresponding to a touch operational mode of the stylus.
[0030] Optionally, at least one of sampling output from the
displacement monitor and transmitting information associated with
the output sampled is responsive toggle state of the switch.
[0031] Optionally, the displacement monitor is an optical detector
for optically sensing the displacement of the tip and for providing
output in response to the sensing.
[0032] Optionally, the pressure sensitive stylus includes a
measuring rod movable with the writing tip, wherein the measuring
rod includes an aperture through which an optical signal of the
optical detector is detected and wherein the output of the optical
detector is altered based on an overlap area between the aperture
and an optical transmission and detecting area of the optical
detector.
[0033] Optionally, the elastomer element is shaped as flat
ring.
[0034] Optionally, the pressure sensitive stylus includes a sleeve
element movable between two partitions formed as part of the
housing, wherein the extremity is fitted through the sleeve element
and fixedly connect to the sleeve element so that tip movement is
confined by movement of the sleeve element.
[0035] An aspect of some embodiments of the present invention
provides for a pressure sensitive stylus for operation with a
digitizer sensor comprising: a housing; a writing tip that is
movable and recedes toward the housing of the stylus in response to
contact pressure applied on the writing tip; an extremity that is
movable together with the writing tip; a switch comprising: a first
conductive layer fixedly positioned on an element positioned around
the extremity; and a second conductive layer facing the first
conductive layer, wherein the second conductive layer is fixed to
the housing; wherein one of the first conductive layer and the
second conductive layer is laminated with a non-conductive
material; and wherein one of the first conductive layer and the
second conductive layer is integrated with an elastomer element
including one or more protrusions extending toward the other one of
the first conductive layer and the second conductive layer; and
wherein physical contact between the first conductive layer and the
second layer responsive to compression of the elastomer element
closes the switch, wherein the physical contact is detected as a
change in capacitance due to an absence of an air gap between the
first and second layer.
[0036] Unless otherwise defined, all technical and/or scientific
terms used herein have the same meaning as commonly understood by
one of ordinary skill in the art to which the invention pertains.
Although methods and materials similar or equivalent to those
described herein can be used in the practice or testing of
embodiments of the invention, exemplary methods and/or materials
are described below. In case of conflict, the patent specification,
including definitions, will control. In addition, the materials,
methods, and examples are illustrative only and are not intended to
be necessarily limiting.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
[0037] Some embodiments of the invention are herein described, by
way of example only, with reference to the accompanying drawings.
With specific reference now to the drawings in detail, it is
stressed that the particulars shown are by way of example and for
purposes of illustrative discussion of embodiments of the
invention. In this regard, the description taken with the drawings
makes apparent to those skilled in the art how embodiments of the
invention may be practiced.
[0038] In the drawings:
[0039] FIGS. 1A, 1B and 1C are simplified schematic drawings of a
known tip pressure detecting system of a pressure sensitive stylus
in a neutral state, a hover state and a touch operational state
respectively;
[0040] FIG. 2 is a simplified graph of a relationship between
applied pressure on a tip of a stylus and displacement of the tip
obtained by a known tip pressure detecting system;
[0041] FIGS. 3A, 3B and 3C are simplified schematic drawing showing
an exemplary tip pressure detecting system of a pressure sensitive
stylus in a neutral position, a hover operational state and a touch
operational state respectively, in accordance with some embodiments
of the present invention;
[0042] FIGS. 4A, 4B and 4C are simplified schematic drawings of
exemplary geometries for an extremity of a tip holder in accordance
with some embodiments of the present invention;
[0043] FIGS. 5A, 5B, 5C and 5D are simplified schematic drawings of
exemplary elastomer elements included in a tip pressure detecting
system, in accordance with some embodiments of the present
invention;
[0044] FIGS. 6A and 6B are simplified schematic drawing showing
assembly of an exemplary tip pressure detecting system, in
accordance with some embodiments of the present invention;
[0045] FIG. 7 is a simplified flow chart of an exemplary method for
altering a response of a pressure sensitive stylus to changes in
pressure in coordination with a switch between a touch and hover
operational state of the stylus, in accordance with some
embodiments of the present invention;
[0046] FIGS. 8A, 8B and 8C are simplified schematic drawings of an
exemplary tip pressure detecting system with an optical sensor, in
accordance with some embodiments of the present invention;
[0047] FIG. 9 is a simplified block diagram of a pressure sensitive
stylus, in accordance with some embodiments of the present
invention;
[0048] FIG. 10 is a simplified block diagram of an exemplary
digitizer system operable to receive input from pressure sensitive
stylus in accordance with some embodiments of the present
invention;
[0049] FIGS. 11A and 11B are simplified schematic drawings of an
exemplary stylus including a normally open contact switch in
accordance with some embodiments of the present invention;
[0050] FIG. 12 is a simplified schematic drawing of components
forming the normally open contact switch in accordance with some
embodiments of the present invention;
[0051] FIGS. 13A and 13B are simplified schematic drawings of an
exemplary stylus including a normally closed contact switch in
accordance with some embodiments of the present invention; and
[0052] FIG. 14 is a simplified schematic drawing of components
forming the normally closed contact switch in accordance with some
embodiments of the present invention.
DESCRIPTION OF SPECIFIC EMBODIMENTS OF THE INVENTION
[0053] The present invention, in some embodiments thereof, relates
to signal transmitting and/or resonating styluses used for
interaction with digitizer sensors, and more particularly, but not
exclusively to styluses that transmit signals responsive to
pressure exerted on their tip.
[0054] According to some embodiments of the present invention, the
tip pressure detecting system determines tip pressure based on
detected displacement of the tip.
[0055] Typically, the system includes a contact switch that
provides input regarding a switch between a hover operational mode
(pen up) and a touch operational mode (pen down). Optionally, when
the tip reaches a threshold displacement the contact switch either
opens if it is a normally closed switch or closes if it is a
normally open switch.
[0056] Due to manufactory tolerances between different styluses and
the demand for same tip travel distance and pressure for tip
activation in the system, variability in the tip pressure
corresponding to the threshold displacement may exist between
different pens, and additional variability may occur over time due
to wear and tear of the components and/or due to changes in
temperature. The present inventors have found that a stable
pressure threshold at a desired pressure level may be reached by
reducing number of accumulating parts tolerances based on a method
of assembly as described herein.
[0057] According to some embodiments of the present invention, the
contact switch is formed by two or more conductive members laid in
two layers and with non-conductive material in between the layers.
Typically, at least one of the two layers is formed with relatively
soft material designed for absorbing mechanical tolerances, thus
providing compensation for manufacturing inaccuracies.
[0058] According to some embodiments of the present invention, the
tip pressure detecting system includes an elastomer element that
provides a counterbalancing pressure on the tip in response to
contact pressure applied on the writing tip. Typically, the
sensitivity and/or the stiffness of the tip is defined by the
properties of the elastomer element as well as an amount of contact
area formed between the elastomer element and an interacting
element that moves with the writing tip and presses against the
elastomer and/or between the elastomer element and wall against
which the elastomer is compressed. In some exemplary embodiments, a
desired non-linear response of the elastomer element is provided by
altering in a stepwise fashion the amount of contact area formed
between the elastomer element and the interacting element around a
pressure defined for switching between hover and touch operational
mode. Typically, increasing the amount of contact area increases
the stiffness or resistive force of the tip to displacement. The
present inventors have found that the non-linear stiffness provides
a better feel for a user using the stylus. Typically, the
non-linear stiffness allows a user to apply low pressure on the
tip, e.g. a comfortable level of pressure to switch to a touch
operational state but also prevents the tip from moving excessively
while a user applies a higher pressure on the tip.
[0059] In some exemplary embodiments, a tip pressure detecting
system additionally includes an optical sensor for monitoring
different pressures applied on the tip based on tip displacement.
In some exemplary embodiments, the optical sensor is only used in
response to detecting a touch operational state of the tip with the
contact switch.
[0060] Alternatively, the optical sensor is not included and
different pressure levels in the working range of the touch
operational state are not monitored.
[0061] For purposes of better understanding some embodiments of the
present invention, as illustrated in FIGS. 3-11 of the drawings,
reference is first made to the construction and operation of a
known tip pressure detecting system of a stylus as illustrated in
simplified schematic drawings of FIGS. 1A, 1B and 1C and to a
simplified representation of a response of the known system to
applied pressure as shown in a graph in FIG. 2.
[0062] In some known styli, a tip pressure detecting system 90
monitors tip contact pressure based on a detected displacement of a
tip holder 11. Tip holder 11 is rigidly connected to a tip 10 in an
axial direction 15. Displacement is measured by a displacement
detector 20 based on which a hover and touch operational state is
defined.
[0063] Typically, when a threshold displacement from a defined
reference point is exceeded, e.g. 50 .mu.m, the stylus switches
from a hover to a touch operational state.
[0064] In one known tip pressure detecting system 90, two different
spring elements 12, 14 provide resilient forces to counterbalance
pressure applied on tip 10 and define a relationship between tip
contact pressure and measured tip displacement. A coil spring 12 is
used to counterbalance low contact pressure on the tip occurring
during a defined hover operational mode (FIG. 1B), while a Nickel
Titanium (NiTi) wire 14 is additionally applied to counterbalance
higher contact pressure and discriminate between the different
pressure levels on the tip occurring during a defined touch
operational state (FIG. 1C). The additional counterbalancing force
provided by the NiTi wire 14 alters the relationship between tip
contact pressure and measured tip displacement. The relationship
between tip contact pressure and measured tip displacement is thus
defined by the resistance of coil spring 12 applied during a hover
operational state, and by coil spring 12 and NiTi wire 14 applied
during a touch operational state (FIG. 2).
[0065] Displacement for activating a touch operational state is
defined by dimensions of the tip holder and a fixed distance
between the tip holder and the NiTi wire. This change in response
may indicate to a user and may also provide indication to
displacement detector 20 that the defined displacement for touch
has been reached.
[0066] During assembly of this tip pressure detecting system,
spring element 12 and NiTi wire 14 are required to be accurately
positioned, so that NiTi wire 14 is activated at the desired
displacement that is defined for switching. Due to accumulation of
tolerances, variations between different styluses may be quite
large making a calibration procedure difficult. The present
inventors have found that tolerances of the system can be reduced
and the calibration of the system can be simplified by using a
single resilient element to provide the two different phases of the
tip response to pressure. The present inventors believe that by
simplifying the assembly and the calibration procedure, costs can
be reduced and the uniformity between styluses can be improved.
[0067] Before explaining at least one embodiment of the invention
in detail, it is to be understood that the invention is not
necessarily limited in its application to the details in
construction and the arrangement of the components and/or methods
set forth in the following description and/or illustrated in the
drawings. The invention is capable of other embodiments or of being
practiced or carried out in various ways.
[0068] Referring now to the drawings, FIGS. 3A, 3B and 3C are
simplified schematic drawings showing a tip pressure detecting
system of a pressure sensitive stylus in a neutral position, a
hover operational state and a touch operational state,
respectively, all in accordance with some embodiments of the
present invention. Typically, tip pressure detecting system 100 is
part of a pressure sensitive stylus. A pressure sensitive stylus
typically includes a tip pressure detecting system as well as other
components, for example processing circuitry, a communication unit
and a power source. According to some embodiments of the present
invention, tip pressure detecting system 100 includes a
displaceable writing tip 10, a displaceable tip holder 11 rigidly
connected to tip 10, an elastomer element 60 that provides a
counter balancing force in response to displacement of tip 10
and/or tip holder 11, and a tip displacement detector 21 for
detecting displacement of tip 10. Typically, tip 10 is displaceable
in a direction 15, e.g. along a longitudinal axis of tip 10 and/or
tip holder 11 responsive to contact pressure applied on tip 10 as
when writing with a stylus.
[0069] According to some embodiments of the present invention, tip
holder 11 includes an extremity 50 that is formed and positioned to
engage elastomer element 60 when pressure is applied on tip 10 and
press against elastomer element 60 with extremity 50 and wall 70.
According to some embodiments of the present invention, extremity
50 includes a base surface 52 and one or more protrusions and/or
protruding parts or surfaces 55 that extend from base surface 52
and provide a relatively smaller contact area with elastomer 60 as
compared to base surface 52 of extremity 50. Optionally, one or
more protrusions and/or protruding surfaces are alternatively
and/or additionally added to wall 70 and/or elastomer 60. In some
exemplary embodiments of the present invention, during low contact
pressure on tip 10, e.g. small displacements of tip 10, protrusion
55 engages and compresses elastomer element 60, while base 52 does
not form direct contact with elastomer element 60. Typically,
during larger displacements of tip 10, both protruding surface 55
and base surface 52 engage and compress elastomer 60. Typically,
the counterbalancing force applied by elastomer element 60 is
significantly larger in response to base surface 52 engaging and
compressing elastomer element 60, as compared with the
counterbalancing force applied when only protruding surface 55
engages elastomer 60.
[0070] According to some embodiments of the present invention,
elastomer element 60 is held stationary with respect to a frame
and/or housing 30 of the stylus. Optionally, elastomer element 60
is held in place by a niche formed in a frame and/or housing 30 at
a tip end of the stylus and/or is supported and/or fixed on a
stopping element and/or wall 70, e.g. with glue. Optionally,
stopping element 70 is formed by frame, partition and/or housing 30
of the stylus.
[0071] According to some embodiments of the present invention, tip
displacement detector 21 detects and monitors displacement of tip
10 from a neutral position in which no pressure or a defined
threshold pressure, e.g. resulting from a 1-20 gm weight is applied
on tip 10. In some exemplary embodiments of the present invention,
tip displacement detector 21 is an optical base sensor that detects
displacement of a measuring rod 24. Typically, measuring rod 24 is
formed from tip holder 11 and/or is rigidly connected to tip holder
11 so that it is displaced together with tip holder 11 and tip 10.
It is noted that although element 24 is referred to as a measuring
rod for convenience, it is not required to be rod shaped.
Optionally element 24 is a flat element.
[0072] In some exemplary embodiments, tip displacement detector 21
is similar to an optical detector as described in incorporated U.S.
Patent Publication U.S. 2010-0051356.
[0073] Alternatively, tip pressure detecting system 100 includes
one of a capacitive or resistive based sensor.
[0074] In some exemplary embodiments, an operational state of a
stylus is defined based on displacement of tip 10 as detected by
tip displacement detector 21. Typically, a threshold displacement
for activating a touch operational state is pre-defined and a
stylus switches from a hover operational state to a touch
operational state when the threshold displacement is reached and/or
exceeded. Likewise a stylus may switch from a touch operational
state to a hover operational state when the displacement of the tip
is diminished past the pre-defined threshold. Typically
displacement is measured relative to a defined neutral position of
tip 10 when no pressure is applied on it and/or pre-defined
reference position. Optionally, output transmitted by a stylus,
e.g. to an associated digitizer sensor and/or host computer is
altered in response to detected displacements of the tip 10. Tip
pressure related output transmitted by a stylus may provide
information regarding an operational state of a stylus. Exemplary
operational states of the stylus may include hover, touch, eraser,
and right click. Optionally, a touch operational state includes a
plurality of operational states based on different pressure levels.
Optionally, output transmitted by the stylus additionally provides
information that can be used for various applicative purposes, such
as altering a width of a line displayed on an associated screen in
response to a stylus stroke. Optionally, in such embodiments, a
width of the line is a function of pressure applied on the tip
while performing the stroke with the stylus.
[0075] Referring now to FIG. 3A, typically during a neutral
position of the stylus tip 10, tip holder 11 is positioned with
respect to elastomer element 60 so that protrusion 55 touches
elastomer element 60 without applying a compressive force on
elastomer 60.
[0076] Optionally, in a neutral position, a protrusion 55 engages
elastomer element 60 with a defined amount of pressure or
alternatively, tip holder 11 is positioned so that there is a
defined gap between protrusion 55 and elastomer element 60.
Typically, the stylus is defined to be in a hover operational state
while the tip is in a neutral position.
[0077] According to some embodiments of the present invention, a
hover operational state is also defined for small displacements of
tip 10 from its neutral position.
[0078] According to some embodiments of the present invention, a
height of protruding surface 55 is defined to correspond with a
defined maximum tip displacement for a hover operational mode
and/or a defined threshold tip displacement for an onset of a touch
operational mode. Typically, the relatively small contact area
between extremity 50 and elastomer element 60 during the hover
operational state when only protrusion 55 engages elastomer element
60, affords a lower counter balancing force applied by the
elastomer and a higher sensitivity of the system to changes in
applied pressure.
[0079] Referring now to FIG. 3B, when pressure is applied on tip 10
during a hover operational state, only a relatively small portion
of elastomer 60 is compressed due to the relatively small surface
area of protrusion 55. Typically, the counterbalance force applied
by elastomer element 60 in this phase is proportional to a surface
area of protrusion 55 and/or a function of the surface area.
[0080] Typically, once tip 10 is displaced by a distance greater
than a height of protrusion 55 as shown in FIG. 3C, the counter
balancing force applied by elastomer element 60 is increased, e.g.
increased in a step-wise manner, the stiffness of the system is
increased and the sensitivity of system 100 to changes in applied
pressure is decreased. In some exemplary embodiments, the step
change in contact area between elastomer element 60 and extremity
50 affords a significant change in the response of system 100 to
applied pressure on the tip. Optionally, elastomer element 60 is
formed from silicone rubber, e.g. with a 20-85 durameter (hardness)
Shore A. In some exemplary embodiments, the response of system 100
to pressure applied on tip 10 is similar to the response shown in
FIG. 2. Optionally, elastomer element 60 is formed from a hardness
that provides 0-250 .mu.m displacement of the tip in response to a
0-0.35 kg forced applied on the tip.
[0081] According to some embodiments of the present invention, the
shape of extremity 50 and the relative size of protrusions 55 and
base 52 with respect to size of elastomer element 60 is customized
to obtain a desired response of system 100 to pressure applied on
tip 10. For example based on the shape and relative size of
extremity 50, the slope of each of the phases as well as the switch
point can be customized.
[0082] According to some embodiments of the present invention, tip
holder 11, extremity 50 including protrusion 55 are part of a
single element that is molded or machined from a same material.
Optionally, tip holder 11 is machined from stainless steel. In some
exemplary embodiments, measuring rod 24 is also an integral part of
tip holder 11, e.g. molded or machined from a same material and/or
is assembled to move together with tip holder 11. Optionally, tip
holder 11 and tip 10 are not separate elements, but are formed as
one element, e.g. made of a single element, machined or molded as
one piece. Typically, housing 30 is molded from plastic, e.g.
liquid crystal polymer.
[0083] The present inventors have found that accumulated tolerances
from different elements in known system 90 may be reduced by
replacing the two spring elements 12 and 14 with a single elastomer
element 60 and by affecting a change in response at a defined
pressure with protrusions included on an extremity 50 of tip holder
11.
[0084] Reference is now made to FIGS. 4A, 4B and 4C showing
simplified schematic drawings of exemplary geometries for an
extremity of a tip holder in accordance with some embodiments of
the present invention. In some exemplary embodiments, exemplary
extremity 50 is shaped in the form of a disk or ring surrounding a
longitudinal axis 150 of tip holder 11. Alternatively, extremity 50
can be shaped as a square plate, hexagon shaped plate, sphere or
other shape. Typically, although not necessarily, extremity 50 is
symmetrical around tip holder 11. In some exemplary embodiments, an
extremity 50 of tip holder 11 includes a protruding surface 55 in
the form of a ring with a rectangular or rounded cross section
(FIG. 4A). Typically, protruding surface 55 when shaped as a ring
has a defined height `h` that protrudes from base surface 52.
Optionally, a width of protruding surface 55 is constant along
height `h`.
[0085] Alternatively, a width of protruding surface 55 is defined
to taper distal end from base 52.
[0086] Referring now to FIG. 4B, in some exemplary embodiments, an
extremity 50 of tip holder 11 is in the form of a plurality of
protrusions 552, e.g. spikes and/or bulges.
[0087] Optionally, a set of three spikes and/or bulges define a
plane. Typically, the spikes or bulges are symmetrically
distributed along base surface 52. Referring now to FIG. 4C,
optionally, an extremity 50 includes a protruding surface 55 in the
form of a ring on which a plurality of bulges 552 are formed. It
will be appreciated that other forms and sizes of protrusions can
be introduced on the extremity. Optionally, bulges 552 are formed
from material applied on the extremity, e.g. UV cured glue which
optionally forms a gel.
[0088] Reference is now made to FIG. 5A showing a simplified
schematic drawing of an elastomer element included in a tip
pressure detecting system in accordance with some embodiments of
the present invention. According to some embodiments of the present
invention, elastomer element 60 is in the shape of a flat ring and
is fitted around tip holder 11. Typically an inner diameter `d` of
elastomer element 60 is large enough to allow free axial movement
of tip holder 11. Typically, the outer diameter `D` and shape of
elastomer 60 is defined to generally correspond to size and shape
of extremity 50.
[0089] Typically, during assembly elastomer element 60 is
inter-disposed between extremity 50 and stopping element 70 (FIGS.
3A-3C).
[0090] Reference is now made to FIGS. 5B, 5C and 5D showing
simplified schematic drawings of alternate exemplary elastomer
elements and extremity of a tip holder included in a tip pressure
detecting system in accordance with some embodiments of the present
invention. Optionally, the desired non-linear response to tip
pressure is provided by an elastomer element composed of two
layers, e.g. layer 61 and layer 62, each having a different
hardness and/or with an elastomer element including one or more
protruding surfaces or bulges, e.g. surface 653 and bulges 656. In
some exemplary embodiments, an elastomer element 60 is molded with
a protruding surface 652 while extremity 50 is flat surface.
Optionally, surface 652 faces stopping element 70 (FIG. 3A).
Alternatively, surface 655 faces extremity 50. Optionally,
elastomer element 60 is molded with a protruding surface 655 on
each of its opposite sides so that protruding surface 655 faces
both stopping element 70 and extremity 50.
[0091] Alternatively and/or additionally, elastomer element 60
includes one or more protrusions 652. Optionally protrusions 652
are used in place of protrusions placed on extremity 50.
Protrusions 652 may be positioned on one or both sides of elastomer
60.
[0092] According to some embodiments of the present invention,
protruding surface 655 and/or protrusions 652 are formed from a
different material than that used to form the base of the
elastomer, e.g. the rest of elastomer 60. Optionally, the
protruding surface 655 and/or protrusions 652 are formed with an
elastomer hardness that is lower than that of the base of elastomer
60. In some exemplary embodiments, elastomer element 60 is shaped
as a flat disk with two different layers 61 and 62. Optionally,
each layer is associated with different elastomer hardness.
[0093] Reference is now made FIGS. 6A and 6B showing simplified
schematic drawings of an exemplary method for assembling a tip
pressure detecting system in accordance with some embodiments of
the present invention. According to some embodiments of the present
invention, during assembly, tip holder 11 is fitted through
elastomer element 60, through a bore of housing 30 and through
sleeve 120 positioned within housing 30.
[0094] According to some embodiments of the present invention,
sleeve 120 is sized and shaped to limit a range of motion of tip
holder 11 within housing 30 and to maintain tip holder 11 in a
reference position while no contact pressure is applied on a tip of
the stylus. Typically the reference position of tip holder 11 is
defined as a position from which tip holder 11 can only move in one
direction when fixed to sleeve 120.
[0095] Optionally sleeve 120 has a hollow cylindrical shape and is
formed from plastic material that is optionally transparent, e.g.
high polish polycarbonate (PC) material.
[0096] According to some embodiments of the present invention,
sleeve 120 is held stationary against wall 71 while tip holder 11
is urged to advance through sleeve 120 toward frame 30 to its
reference position where all spaces between the elements are
closed, e.g. with a preload of 1-10 gm. In some exemplary
embodiments a jig 180 is used to hold sleeve 120 against wall 71.
According to some embodiments of the present invention, while tip
holder 11 is positioned in the reference position and sleeve 120 is
positioned against wall 71, e.g. the reference position of sleeve
120, sleeve 120 is glued to tip holder 11 so that the reference
position is fixed. Once tip holder 11 is glued and/or fixed to
sleeve 120 at the reference positions, tolerances associated with
displacement of the tip and/or tip holder can be defined by
tolerances of one moving part and pre-load tolerances. Optionally,
tip holder 11 is supported with a support 49 while tip holder is
urged toward housing 30. In some exemplary embodiments, a reference
position of tip holder 11 is defined when elastomer element 60 is
engaged by extremity 50 and wall 70, e.g. optionally with a defined
pre-load. Optionally, a nominal force, e.g. self-weight--10 gm
force is applied on tip holder 11 to urge extremity 50 and
elastomer element 60 toward housing 30, e.g. without compressing
elastomer 60. Optionally, a weight of tip holder 11 defines the
pre-load for the reference position. Optionally, assembly is
performed while tip holder 11 and housing 30 are aligned in the
gravitational direction so that the weight of the tip holder 11 and
elastomer 60 urges them toward wall 70 of housing 30.
[0097] According to some embodiments of the present invention, at
the reference position sleeve 120 is fixed to tip holder 11, e.g.
glued. Typically, once sleeve 120 is fixed to tip holder 11, jig
180 is removed. Optionally, jig 180 is constructed from a metal
material, e.g. stainless steel. Typically, jig 180 is horseshoe
shaped so that it can be fitted around tip holder 11 and hold 120
in place. The present inventors have found that by stacking the
elements and fixing sleeve 120 to tip holder 11 while the elements
are stacked, many of the accumulated tolerances from the different
interacting parts can be eliminated.
[0098] Reference is now made to FIG. 7 showing a simplified flow
chart of an exemplary method for altering a response of a pressure
sensitive stylus to changes in pressure in coordination with a
switch between a touch and hover operational state of the stylus in
accordance with some embodiments of the present invention.
According to some embodiments of the present invention, a maximum
allowable tip displacement during a hover operational state is
defined. Alternatively or additionally, a maximum tip pressure for
a hover operational state is defined (block 701). Size and/or shape
of a protruding surface are defined to provide a desired response
and stiffness (block 702).
[0099] The counterbalancing force that will be applied on the tip
during a hover operational state can be defined by defining a
surface area and/or shape of the protrusion. Typically larger
contact surface areas provide a stiffer feel on the tip.
[0100] According to some embodiments of the present invention, the
defined extremity is positioned next to elastomer element providing
the counterbalancing force. Typically, a neutral position of the
tip is defined from which displacements are measured (block 703).
Typically, the neutral position corresponds to the position of the
tip when the extremity of the tip holder engages the elastomer
element without applying compressive forces on the elastomer
element. In some exemplary embodiments during a calibration
procedure, a displacement detector detects displacement of the
stylus and the expected non-linear change in response in the
vicinity of the switch displacement is identified.
[0101] Switching between hover and touch is defined to occur at the
identified point and the identified point is stored in the stylus
memory (block 704).
[0102] Reference is now made to FIGS. 8A, 8B and 8C showing
simplified schematic drawings of a movable tip system and optical
sensor for reporting a switch in an operational state of a stylus
in accordance with some embodiments of the present invention.
According to some embodiments of the present invention,
displacement of a stylus tip 10 is detected with an optical sensor
210 that typically includes an emitter 29 emitting an optical
signal, e.g. light rays 27 across an area 22, and a detector 28
that detects the optical signal emitted from the emitter 29 across
area 22 (FIG. 8A). In some exemplary embodiments, optical sensor
210 is similar to the optical sensor described in incorporated U.S.
Patent Publication U.S. 2010-0051356. In some exemplary
embodiments, a measuring rod 240 of a tip holder 11 includes an
aperture 245 through which the optical signal from emitter 29 can
be received by the detector 28 of sensor 240. Typically, the amount
of light received by detector 28 depends on the amount of overlap
222 between aperture 245 and area 22 across which optical signal 30
is transmitted and received. Typically, overlap area 222 is a
function of the tip displacement along direction 15. According to
some embodiments of the present invention, aperture 245 is shaped
to provide a step-wise change in overlap area 222 at a pre-defined
displacement of tip 10. Optionally, aperture 245 is shaped as a
small rectangle over (or alternatively below) a larger rectangle.
Typically, the step-wise change in overlap area 222 provides a
non-linear change in a response of the tip pressure detecting
system around the pre-defined displacement at which the step-wise
and/or non-linear change takes place.
[0103] According to some embodiments of the present invention, the
pre-defined displacement at which the step-wise change takes place
is the displacement defined for switching between a hover and touch
operational state. In some exemplary embodiments, the non-linear
varying aperture shape is used in conjunction with protrusion 55 on
extremity 50 to further accentuate and/or mark a displacement
corresponding to a switch between hover and touch. Optionally, the
non-linearly shaped aperture is used in place of protrusion 55 on
extremity 50.
[0104] Reference is now made to FIG. 9 showing a simplified block
diagram of a pressure sensitive stylus in accordance with some
embodiments of the present invention.
[0105] According to some embodiments of the present invention, a
pressure sensitive stylus 200 includes a tip pressure detecting
system 100, a controller 110, a transmitting unit 130, one or more
operation switches 160, and a power source 140, e.g. one or more
batteries and/or super capacitor. Typically, tip pressure detecting
system 100 includes tip displacement detector 21, tip holder 11
with extremity 50 and elastomer element 60.
[0106] Optionally, controller 110 and/or control capability is
included in tip pressure detecting system 100. Optionally, stylus
200 is partially or fully powered from an outside source, e.g. an
external excitation signal provided by a digitizer system.
[0107] According to some embodiments of the present invention,
controller 110 controls operation of stylus 200. In some exemplary
embodiments, controller 110 additionally provides processing and
memory capability, e.g. for operation of tip pressure detecting
system 100. In some exemplary embodiments, output from tip pressure
detecting system 100 and/or operation switches 160 is processed and
optionally stored in controller 110.
[0108] Typically output from stylus 200 is transmitted by a
transmitting unit 130, and received by an associated digitizer
system. In some exemplary embodiments, output from tip pressure
detecting system 100 is encoded by controller 110 prior to being
transmitted by transmitting unit 130. Optionally, one or more
states of one or more operation switches is encoded and
transmitted. In some exemplary embodiments, transmitting unit 130
additionally includes reception ability to provide two way
communication, e.g. with a digitizer system. Additionally, stylus
200 may comprise, for example, aspects similar to aspects of
styluses described in incorporated U.S. Patent Application
Publication No. 20080128180.
[0109] Reference is now made to FIG. 10 showing a simplified block
diagram of a digitizer system including a digitizer sensor in
accordance with some embodiments of the present invention. The
digitizer system 300 may be suitable for any computing device that
enables interactions between a user and the device, e.g. mobile
computing devices that include, for example, FPD screens. Examples
of such devices include Tablet PCs, pen enabled lap-top computers,
tabletop computer, PDAs or any hand held devices such as palm
pilots and mobile phones.
[0110] According to some embodiments of the present invention,
digitizer system 300 includes a sensor 312 for sensing output of
stylus 200 and/or tracking position of stylus 200. In some
exemplary embodiments sensor 312 includes a patterned arrangement
of conductive strips or lines that are optionally arranged in a
grid including row conductive strips 322 and column conductive
strips 324, also referred to as antennas. In some exemplary
embodiments, sensor 312 is transparent and is optionally overlaid
on a flat panel display (FPD). According to some embodiments of the
present invention, sensor 312 is a capacitive based sensor that
simultaneous detects a stylus and one or more finger touches.
[0111] Typically, circuitry is provided on one or more printed
circuit boards (PCBs) 340 positioned in proximity to touch sensor
312. One or more application specific integrated circuit (ASICs)
316 positioned on PCB 340 comprise circuitry to sample and process
the sensor's output into a digital representation. Digital output
is optionally forwarded to a digital unit 319, e.g. a digital ASIC
unit mounted also on PCB 340, for further digital processing.
Typically, output from digital unit 319 is forwarded to a host 320
via an interface 323 for processing by the operating system or any
current application.
[0112] According to some embodiments, digital unit 319 also
produces and sends a triggering pulse to at least one of the
conductive lines, e.g. a trigger pulse with frequency of 10-300
KHz. In some exemplary embodiments, finger touch detection is
facilitated when sending a triggering pulse to the conductive
lines.
[0113] According to some embodiments of the invention, digital unit
319 determines and/or tracks the position of stylus 200 as well as
other of physical objects, such as finger 346, and/or an electronic
tag touching the digitizer sensor from the received and processed
signals. According to some embodiments of the present invention,
digital unit 319 determines the tip pressure applied on stylus 200
based on encoded signals transmitted by the stylus, e.g. analog
encoded signals. In some exemplary embodiments of the present
invention hovering of an object, e.g. stylus 200, finger 346 and
hand, is also detected and processed by digital unit 319. According
to some embodiments of the present invention, hovering and touching
stylus is differentiated by signals transmitted by the stylus, e.g.
analog encoded signals.
[0114] According to some embodiments of the present invention,
digitizer system 300 includes a stylus garage 365 for storing
stylus 200 while not being used. Optionally, stylus garage 365
includes a charger 367 for charging a battery of stylus 200.
[0115] Optionally, stylus 200 is powered with a wire, based in
stylus garage 365 or with electrical decoupling. Optionally
digitizer 300 includes an excitation coil surrounding sensor 312
for transmitting a triggering signal to stylus 200.
[0116] Typically, stylus 200 is operable to be used with a
capacitive touch screen.
[0117] Optionally, stylus 200 can be added as a stand-alone product
to an existing capacitive touch screen that includes circuitry that
supports stylus interaction.
[0118] Digitizer systems used to detect stylus and/or finger tip
location may be, for example, similar to digitizer systems
described in incorporated U.S. Pat. No. 6,690,156, U.S. Pat. No.
7,292,229 and/or U.S. Pat. No. 7,372,455. Embodiments of the
present invention will also be applicable to other digitizer
systems known in the art, depending on their construction.
Embodiments of the present invention will also be applicable to
other digitizer sensors known in the art, e.g. sensors comprising
loop coils.
[0119] Reference is now made to FIGS. 11A and 11B showing a
simplified schematic drawing of an exemplary stylus including a
normally open contact switch and to FIG. 12 showing a simplified
schematic drawing of components forming the normally open contact
switch, all in accordance with some embodiments of the present
invention.
[0120] According to some embodiments of the present invention, a
stylus 410 includes a contact switch 450 formed from a conductive
ring 260 and a plate 270 including at least two conductive elements
275 that are isolated from each other, each connected to a terminal
279.
[0121] According to some embodiments of the present invention,
plate 270 is fixedly attached to wall 70 of housing 30 and
conductive ring 260 is fitted over elastomer element 60 and moves
together with elastomer element 60 and tip holder 11 in response to
pressure applied on tip 10. Typically each of elastomer 60,
conductive ring 260 and plate 270 are ring shaped and fit around
tip holder 11. Typically, conductive ring 260 is formed from a soft
conductive material that is securely fitted around tip holder 11,
so that conductive ring 260 does not move in relation to tip holder
11. Optionally, conductive ring 260 is formed from conductive
silicon including carbon or other conductive particles such as
nano-tubes. Optionally, conductive ring 260 is formed from blend,
e.g. mix of conductive material and/or conductive particles and one
or more of rubber, thermoplastic polyurethane (TPU), and
polyoxymethylene (POM). Optionally, conductive ring 260 is formed
using double injection molding or insert molding.
[0122] Alternatively or additionally plate 270 is formed from a
soft and/or pliable material.
[0123] In order to attach conductive ring 260 to base portion 652,
a rigid member (not shown) may optionally be provided as part of or
attached to base portion 652, which will press into conductive ring
260 and attach it to base portion 652.
[0124] According to some embodiments of the present invention,
conductive ring 260 includes a plurality of openings and/or through
going holes 262 and elastomer 60 is formed with bulges, prongs
and/or protruding elements 656 that are matched with holes 262 and
protrude through openings 262. According to some embodiments of the
present invention, protruding elements 656 provide for separating
conductive ring 260 from plate 270 during a hover operational mode
of stylus 410 (FIG. 11A). According to some embodiments of the
present invention, during a touch operational mode, protruding
elements 656 collapse and/or compress against plate 270 in response
to movement of tip holder 11 and conductive ring 260 comes into
contact with conductive elements 275 and shorts terminals 279 (FIG.
11B). According to some embodiments of the present invention,
protruding elements 656 provides a defined resilient force that
prevents movement of tip holder 11 while stylus 420 is held upside
down and releases contact between ring 260 and plate 270 when
pressure on tip 10 is released. Typically, openings 262 are defined
to be larger in diameter than protruding elements 656 to
accommodate for deformation of protruding elements 656 during
compression. Typically, conductive elements 275 are connected to
circuitry of stylus 410, e.g. a PCB of stylus 410 and/or controller
110 (FIG. 9). According to some embodiments of the present
invention, a touch operational state is defined and/or sensed in
response to detecting and/or sensing a short between terminals
279.
[0125] Optionally, additional pressure applied on tip 10 compresses
the base portion 652 of elastomer 60. Typically, the resilient
force provided by base portion 652 is greater than that provided by
protruding elements 656. Optionally movement of tip holder 11 is
optically detected with tip displacement detector 21. Optionally,
sensing with tip displacement detector 21 is only activated in
response to sensing a pen-down state contact switch 450.
Alternatively, contact switch 450 is used in place of tip
displacement detector 21 and stylus 410 does not provide for
monitoring different pressure levels in a touch operational
mode.
[0126] Reference is now made to FIGS. 13A and 13B showing a
simplified schematic drawing of an exemplary stylus including a
normally closed contact switch and to FIG. 14 showing a simplified
schematic drawing of components forming the normally closed contact
switch, all in accordance with some embodiments of the present
invention.
[0127] According to some embodiments of the present invention, a
stylus 420 includes a normally closed contact switch 455 formed
from a conductive ring 265 and plate 270 including at least two
conductive elements 275 that are isolated from each other each
connected to a terminal 279.
[0128] According to some embodiments of the present invention,
plate 270 is fixedly attached to wall 72 of housing 30 and
conductive ring 265 is securely fitted around tip holder 11, so
that ring 260 moves together with tip holder 11 but does not move
in relation to tip holder 11. Typically, conductive ring 260 is
formed from a soft conductive material. Optionally, conductive ring
260 is formed from conductive silicon including carbon or other
conductive particles such as nano-tubes. Optionally, conductive
ring 260 is formed from blend, e.g. mix of conductive material
and/or conductive particles and one or more of rubber,
thermoplastic polyurethane (TPU), and polyoxymethylene (POM).
[0129] According to some embodiments of the present invention,
elastomer 60 is formed with a protruding element 655 in the form of
a ring that faces and touches wall 70 of housing 30. Optionally,
elastomer element 60 includes a plurality of protruding elements
656. Optionally, elastomer element 60 is flat so that the base 652
is compressed in response to applied pressure, e.g. elastomer
element 60 does not include protruding elements 656.
[0130] According to some embodiments of the present invention, in
response to pressure applied on tip 10, protruding elements 656 are
pushed up against wall 70 and are compressed and tip holder 11 is
displaced. Typically, compression of protruding elements 656
provides a resilient force against pressure applied on tip 10.
According to some embodiments of the present invention,
displacement of tip holder 11 during a touch operational mode of
the stylus separates conductive ring 265 from plate 270 opens
contact switch 455, e.g. terminals 279. Typically, conductive
elements 275 are connected to circuitry of stylus 420, e.g. a PCB
of stylus 420 and/or controller 110 (FIG. 9). According to some
embodiments of the present invention, a touch operational state is
defined and/or sensed in response to detecting and/or an open state
of contact witch 455.
[0131] Optionally, additional pressure applied on tip 10 compresses
the base portion 652 of elastomer 60. Optionally movement of tip
holder 11 is optically detected with tip displacement detector 21.
Optionally, sensing with tip displacement detector 21 is only
activated in response to sensing a pen-down state with contact
switch 455.
[0132] Alternatively, contact switch 455 is used in place of tip
displacement detector 21 stylus 420 does not provide for monitoring
different pressure levels in a touch operational mode.
[0133] It is noted that the method for assembling a tip pressure
detecting system as described herein can be similarly applied to
stylus 410 and 420.
[0134] It will be appreciated that the two-state switch described
above may be used with or without pressure monitoring mechanism. It
may also be used for controlling different power modes and
different operation modes of the stylus, such that when no touch is
sensed, the stylus is in power save (sleep) mode, and wakes up upon
touch where pressure is applied on the tip. The different modes can
also be used for changing report rate or report content between
hover and tip.
[0135] In alternative embodiments, the switch may be implemented as
a capacitive switch including two conductive layers separated by an
air gap where at least one of the layers is covered and/or
laminated with a thin non-conductive layer having high dielectric
coefficient. When there is an air gap between the two conductive
layers, such as when no pressure is applied, the dielectric
coefficient drops and the capacitance drops due to the dielectric
coefficient and the distance between the layers. This provides for
significant difference in capacities and therefore discriminating
between the states of pressure and no pressure. Optionally, one of
the conductive layers is elastomer element 60 and/or is integral to
elastomer element 60. Optionally protruding elements 656 define the
air gap between the conductive layers.
[0136] The terms "comprises", "comprising", "includes",
"including", "having" and their conjugates mean "including but not
limited to".
[0137] As used herein, the singular form "a", "an" and "the"
include plural references unless the context clearly dictates
otherwise.
[0138] Whenever a numerical range is indicated herein, it is meant
to include any cited numeral (fractional or integral) within the
indicated range. The phrases "ranging/ranges between" a first
indicate number and a second indicate number and "ranging/ranges
from" a first indicate number "to" a second indicate number are
used herein interchangeably and are meant to include the first and
second indicated numbers and all the fractional and integral
numerals therebetween.
[0139] It is appreciated that certain features of the invention,
which are, for clarity, described in the context of separate
embodiments, may also be provided in combination in a single
embodiment. Conversely, various features of the invention, which
are, for brevity, described in the context of a single embodiment,
may also be provided separately or in any suitable sub-combination
or as suitable in any other described embodiment of the invention.
Certain features described in the context of various embodiments
are not to be considered essential features of those embodiments,
unless the embodiment is inoperative without those elements.
[0140] Although the invention has been described in conjunction
with specific embodiments thereof, it is evident that many
alternatives, modifications and variations will be apparent to
those skilled in the art. Accordingly, it is intended to embrace
all such alternatives, modifications and variations that fall
within the spirit and broad scope of the appended claims.
* * * * *